Flashcards in Anaesthetics / Peri-Op Deck (70):
Describe the grading used to asses patient fitness for surgery.
* ASA1: Healthy Patient
* ASA2: Mil Systemic Disease
* ASA3: Severe Systemic Disease
* ASA4: Life threatening
What tests make up a pre surgical assesment at low surgery and ASA grades?
* ECGs considered >40yrs
* U+Es / eGFR / FBCs >60yrs Urine Test
* Preg: fertile women UTI
* Glucose for DM
What pre op investigations may be done on certain patients?
* CXr (infection)
* ECG (arrhythmias)
* FBCs (anemia + crp)
* Hemostasis / Coagulatiuon (warfarin or genetic clotting disorders)
* eGFR / Liver Function (GA metabolism / excretion)
* Random Glucose (Diabetes)
* Blood Glucose (Acidosis / Alkalosis / Lactate)
* Lung Function Tests (COPD)
* Group + Save (High risk for bleeds)
Why is asking about reflux an important part of a pre op assesment
Must use endotracheal intubation, LMAs carry a too high risk for aspirationGive PPI + H2 antagonist prior to surg
What complications will anemic pts. liekly suffer from during surgery?
* Poor Wound Healing
What allergies indicate an allergy to propofol
Egg / Soya
Name 2inherited conditions that cause problems with surgery.
* Rise in temp due to sever muscle contraction when subjected to GAs
* Treated with dantrolene + cooling blanket Suxamethonium Apnoea
* Pt. cannot metabolise suxamethonium and must be given FFP at the end of the OP.
What are asthmatic patients more likely to suffer from when anethetised?
How do you asses a difficult airway
Look at the external airway
* Micrognathia (Small Jaw)
* Facial Hair
* Poor Dental Hygiene
Evaluate 3/3/2 rule
* 3 fingers in the mouth vertically
* 3 fingers from chin to hyoid
* 2 fingers from hyoid to thyroid notch
* Class 1: Soft Palate Visible
* Class 2: Uvula Visible
* Class 3: Uvual Partially Visible
* Class 4: Soft Palate Not Visible
* Foreign Bodies
Should be extended
What drugs need to be stopped before OPsHow long before OPs are they stopped
* Clopidogrel (1 Week)
* Aspirin (1 Week)
* Warfarin (1 Week) BP Meds
* ACEi (Day of surg) Ca2+ Channel Blockers (Day of Surg)
* Beta Blockers (Day of Surg)
* Thiazide diuretics (Day of Surg/Continue when back on fluids) Diabetic Meds
* Oral Hypoglycemics (Day of Surg (Changes in renal function))
* Short Acting Insulin (Day of Surg) Thyroid
* Thyroxine (Take in Morn and following surg) NSAIDS
* Short Acting (2/3 days)
* Long Acting (1 Week) Others
* COCP (4 Weeks / Restart 2 Weeks Post)
* Hormone Replacment (4 Weeks / Restart 2 Weeks Post)
* Herbal Meds (2 Weeks) Nutrition
* Food (6 Hours)
* Water (2 Hours)
* Breast Milk (4 Hours)
How do you reverse wargarinisation in emergency surgery?
* Vitamin K (6-12hrs) FFP
* Immediate but causes fluid overload
* Needs to thaw Prothrombin Complex Concs. (Beriplex/Octaplex) 2/7/9/10 and Vit K
* Expensive £1,000
What happens concerning MRSA prior to surgery
All Pts. swabbed prior to surg
* Nasal Mucosa
* Skin Lesions
* Tracheostomies Asymptomatic
* Treated with Mupirocin Nasally TDS for 5 days
* Clorhexidine Gluconate wash 5 days
* Addition Peri Op Abxs given Symptomatic
* IV Vancomycin
How does induction of anesthetics begin?
* Propofol IV to induce the initial unconsciousness in a patient
* Thiopental can be used for rapid sequence induction
* Etomidate or ketamine can be used in cardiovascularly unstable patients (won't depress cardiac output)
* Sevoflurane can be used as a volatile inducing agent
How do you maintain an anesthetist pt.?
Sevoflurane is an inhaled isopropyl ether which can be used for both induction and maintenance of general anaesthesiaIsoflurane and desflurane are other maintenance gases (cheaper than sevo)Propofol infusion can be used if volatiles must be avoided eg. In malignant hyperthermia
Why is it important to administer muscle relaxants and which drugs are used to do this?
* Important to stop the patient from moving and to relax abdominal muscles to make incisions easier
* Atracurium, rocuronium or suxamethonium
Why are analgesics important when pt is anesthetised?Which drugs are used?
* Prevent nociception (pain signalling) to prevent increases in heart rate, blood pressure, etc. Drugs
* Fentanil is generally used throughout surgery
* Morphine is generally used following the procedure Inhaled N2O acts as an analgesic but is likely to cause nausea and vomiting in patients with risks of post-op N&V
How is a pt. monitored when anesthetised?
Capnography (CO2) monitoring
* Possibly the most important monitor
* Can see that muscle relaxant is wearing off if the patient begins to form 2 peaks on capnography – shows that the patient is breathing = diaphragm movement = muscles not relaxed
* ECG – check for arrhythmias
* Pulse oximetry
* Blood pressure
What are the problems and contraindications of bag mask ventilation
Problems with bag-valve-mask ventilation
* Harder on men with large beards
* Harder on patients with high BMI (>26)
* Age >55
* History of snoring and sleep apnoea – oropharyngeal airway will help with this
* Lack of teeth Contraindication
* Complete airway obstruction (air will all go to stomach)
* Paralysis/anaesthesia (risk of aspiration is increased)
Advantages of tracheal intubation?How do you confirm endotracheal tube is correctly located?
* Least likely to aspirate
* Ensure air reaches lungs not stomach Ventilation should
* Give a capnograph reading
* Make chest rise and fall
* Audible on ascultation
During intubation what has happened if only one side of the chest is rising and falling and how do you deal with this?
The tube has gone down either the L/R bronchi therefore you should pull back a bit on the endotracheal tube. (usually the R. bronchus)
Problems and contraindications for endotracheal intubation
Problems Mallampati scores of 4 are hard to intubate
* Use fibre optic laryngoscopy Its much harder to do
* Stop and bag mask ventilate back to 100% O2 before tryign again May accidentally enter the stomach increasing chance of aspiration
* Capnograph reading can confirm this Contraindications Spinal problems
* Epiglottal infection
* Mandibular Fracture
* Oropharyngeal haemorrhage
When are SGA devices used?What are the different types?
* Rescue ventilation when endotracheal intubation not possible.
* Short simple operations
* Cardiac arrests Types
* iGEL (cardiac arrest)
Disadvantages of SGAs over endotracheal intubation?
Airway not fully protected so increased risk of aspiration.
What is rapid seqeunce induction?
Intubation in an emergency setting where the patient is unfasted and therfore has a much higher risk of aspiration
How do you perform a rapid sequence induction
Pre oxygenate to 100% sats
* Gives 5 mins without needing to ventilate Intubation directly after drug administration
* No bag/mask or SGAs Use rapid sequence drugs
* Thiopental + suxamethonium
What steps are required to wake a patient up?
* Stop giving gases Neostigmine
* reverse effects of muscle relaxants Naloxone
* reverse effects of opiates Flumazenil
* reverse effects of benzodiazepines
* Patients must be able to maintain their own airway before ventilation is removed.
What are the 6 criteria a patient must meet before they are discharged from the recovery room
* Patient is fully conscious and able to maintain a clear airway O2 Sats are sufficient CVS is normal
* Pulse/BP/Peripheral perfusion
* Pain and emesis under control
* Temperature is normal
* Oxygen and IV therapy are prescribed if needed
When are tracheostomies indicated?
* Facial Fractures
* Epiglotal infection
* Forgein Body
* Angiodema Chronic (less iritating than endotracheal)
* Wean patients off ventilatory support
* Laryngeal tumour
* Clearing of secretions (cystic fibrosis)
How do tracheostomies need to be cared for?
* Inner tube replaced every 5-7 days
* Skin around opening No Speech
* Speaking valves implanted No Humidification
* Keep patients well hydrated Difficulty swallowing
* Nutrional assesment Can't Cough
* Suction to reduce secretions
What are the different classifications of wound contamination?
* Non emergency with no trauma
* No inflammation
* No entry to resp/GI/HPB/urinary tracts Clean-contaminated
* Clean Emergency cases
* Non emergency involving resp/GI/HPB/urinary tracts Contaminated
* Gross spillage from resp/GI/HPB/urinary tracts
* Non purulent inflammation
* Trauma <4hrs
* Chronic open wounds Dirty
* Purulent inflammation
* Pre perf or resp/GI/HPB/urinary tracts
* Trauma < 4
How do you identify and treat a surgical site infection
* Obs (Temp)
* FBC (White cells)
* Blood Cultures
* Swabs of wound site Treatment
* Abx based on micro result
* Wound may need opening/debridement
What are the different types of post-op surgical infections?
* Surgical Site Infection Post-op chest infection
* Wound pain leads to shorter breaths causing stasis of air in lung Urinary tract infection
* Catheter insertion Bacteraemia
* Anastomotic leakage
How do you reduce the risk of surgical site infections
* Shower before surgery
* Remove hair around area using electrical clippers Antibiotic prophylaxis
* Involving insertion of a prosthesis/implant
* Anything other than clean surgery
* Skin prep using antiseptic
* Scrubbing and maintain sterile field Cover wounds with dressings
* Avoid futher contact for 72hrs
What should the urine output be?What are the causes of low urine output?
* Or 400/500ml over 24hrs for adults Causes
* Pre-renal (dehydration)
* Renal (CKD/AKI)
* Post-renal (blocked catheter)
What should fluid intake/output be for an adult?Of the output how much of this is made up in urine?
Difference betweeen crystalloid and colloid solutions?
Crystalloid solutioins contain water and electrolytes whereas colloids also contain proteins and other large molecules to help keep the osmotic and oncotic pressures similiar to that of plasma.
What are the different types of crystalloid solution and when would you use them?
Normal Saline (NS)
* Good for fluid ress Dextrose
* Use when BMs are low
* Isotonic when it goes in, however once dex is used up becomes hypotonic causing oedema Hartman's
* Most physiologically similiar to plasma Potassium Safe rate is 5mmol/hr otherwise cardiac abnormalities
* Causes bradycardia
Why are colloids not used anymore?
* Greater risk of adverse reaction due to allergy to some of the bigger molecules within them
* No evidence that they are any better than crystalloids
When administering fluids what must you consider?
Maintence requirments Na+ + K+ + Cl-: 1mmol/Kg/24hrs
* Water: 25ml/Kg/24hrs
* Glucose: 50-100g/24hrs Pre-existing deficits Dehydration
* Give extra fluid in 500ml bolus over 15 mins
* Elderly/Heart/Kidney failure need 250ml bolus
* Electrolyte deficiency Abnormal ongoing losses Diarrhoea K+ + HCO3- lost Vomiting H+ + Cl- lost
* High stoma output
* Enterocutaneous fisulas
When giving fluid resus to a pt. in shock what must you consider?
Do not dilute the blood to much with loads of fluid
* Give blood where possible Do not infuse too fast
* Big changes in pressure can dislodge clots cause embolic events
What are the problems with NS solutions as a maintence dose?
Missing out on other electrolytes such as K+ and Ca2+
* More sodium than normal blood cause hypernatraemia
* Overexcretion of phosphates causing hypocalcaemia
What are the causes of exessive fluid loss and how would you treat them?
Urine Diabetes mellitus
* Glucose control Diabetes insipidus
* ADH agonist (Desmopressin) GI tract Diarrhoea + High Stoma Output Antimotility drugs
* Loperimide, other opioids, antihistamines, antipsychotics, and anticholinergics
* Pts should drink WHO solution instead of water as is isotonic Vomiting
* Give pts anti-emetics Bleeding Occult Bleed
* Consider stopping anti-coagulants
* Tranexamic acid Unseen surgical bleed
* Back to theatre to stop the bleed
Signs and symptoms of dehydration
* Dry mucosal linnings
* Tachycardi with a weak pulse
* Reduced skin turgor
* Reduced sweating
During a fluid resus how much fluid should be given before seeking expert help?
>2000ml of fluid usually in 500ml boluses over 15 mins
When should pts be switched over from IV fluids to enteral feeding?
As soon as possible. If they are able to tolerate enteral feeding (can use NG tube) then there is no reason to keep them on IV fluids
After surgery what must you ensure before starting to feed patients
Passing faeces/flatus as this means they dont have ileus
Definition of chronic pain
Pain > 3 months after healing has occured
Which tract does pain travel up the spinal cord
2 types of pain fibres
A-delta (sharp)C fibres (dull)
What is haematocrit and what is the normal range
Meausre of conc. of blood45%
Normal reference range for a) sodiumb) potassiumc) glucose
a) 135-145b) 3.5-5c) 3.5-5.5
what is IV 5% dex used for?
What IV fluid is best for resuscitation (increasing extracellular fluid levels).
Hartman's (best)IV fluidDextrose (worst)
What is a colloid?
IV fluid with large molecules in such as starch and proteins.
What happens to tight junctions in sepsis?
become much more leaky allowing fluid and large molecules to enter the tissue from cappilaries.
What is a crystalloid
Why are colloid's not used anymore?
No evidence to suggest large proteins and starch stay within plasma for terribly long and in sepsis can leak into tissues and exert a counter osmotic effect.
What causes confusion?
SepsisHypoxiaHypoglycemiaConcussionDrug inducedUnderlying confusion (rule out others first)
Basic maintence dose for healthy young individual
1 bag hartman's1.5 bags 5% dex20mmol K per bag
What does TPN stand for and what is it
Total parenteral nutrition (TPN) is a method of feeding that bypasses the gastrointestinal tract. Fluids are given into a vein to provide most of the nutrients the body needs. The method is used when a person cannot or should not receive feedings or fluids by mouth.
Mneumonic for macrocytic anaemias?
FAT RBC :Foetus, Alcohol, Thyroid, Reticulocytosis (chronic blood loss), B12/Folate, Cirrhosis.
causes of Normocytic Anaemia?
Acute blood loss, anaemia of chronic disease, marrow infiltration, haemolytic anaemia.
When would you send someone for a coagulation sreening pre op?
PMH/FH of unusal bleedingpost-surgical bleeding
What type of antiplatlet therapy is stopped before routine surgery and which type is continued
Aspirin continuedClopidogrel stopped (7 days before op)
Mneumonic for microcytic anaemia
The mnemonic "Find Those Small Cells" is useful: Fe deficiency, Thalassaemia, Sideroblastic anaemia, Chronic disease.
Why are malignant cells more prone to clotting?
Tumor cells to produce and secrete procoagulant/fibrinolytic substances and inflammatory cytokines
What is ITP
Idiopathic thrombocytopenic purpura (ITP) is a bleeding disorder in which the immune system destroys platelets.Same as immune thrombocytopenia
How do you reverse the effects of warfarin
6-12 hrs Vit K2-4 hrs Prothrombin Complex Concentrate (PCC) (Octaplex, beriplex)
Vitamin K dependent clotting factors